Stainblockers are commonly applied to fibrous substrates to prevent stains. However, the use of stainblockers often interferes with the dyeing of fibrous substrates. Generally, because stainblockers provide resistance to staining, they also provide resistance to dyeing. Stainblockers may also undesirably interact with dye to cause bleeding or dye removal.
In general, there are two classes of dyeable fibers. One class of dyeable fibers, commonly referred to as “acid dyeable fibers,” have cationic chemical functionalities which readily accept dyes with anionic chemical functionalities, also commonly referred to as acid dyes. A second class of dyeable fibers, commonly referred to as “cationic dyeable fibers,” have anionic chemical functionalities which readily accept dyes with cationic chemical functionalities, also commonly referred to as basic dyes.
Typical stainblockers have anionic chemical functionalities which react with the cationic chemical functionalities of acid dyeable fibers thereby blocking sites where staining might occur. Unfortunately, typical stainblockers also block sites where dyeing can occur, especially where acid dyes are used. Accordingly, when stainblocker application precedes acid dye application, the dye is hindered from interacting with acid dyeable fibers thereby requiring additional applications of the dye. Therefore, with respect to acid dyes and dyeable fibers, it is conventional to proceed with dye application before applying stainblocker. One notable exception is U.S. Pat. No. 4,680,212, which discloses the application of a stainblocker and a fluorochemical during the manufacture of acid dyeable fibers. The resulting fibers are then dyed with acid dyes at elevated temperatures. While this reference, and perhaps other like it, address problems associated with application of stain blockers and dyes to acid dyeable fibers, unsolved problems remain regarding application of stainblockers and cationic dyes to cationically dyeable fibers.
Unfortunately, the anionic chemical functionalities of typical stainblockers often undesirably interact with the cationic chemical functionalities of cationic dyes. Consequently, the application of stainblocker after dye application causes removal of the dye, commonly known as “bleeding.” One solution to the problem of dye bleeding is the subsequent reapplication of the dye as exemplified by U.S. Pat. No. 6,811,574. Nevertheless, it would be advantageous to find a method of applying cationic dye and stainblocker to cationically dyeable fibers which reduces or eliminates dye bleeding and the need for further reapplication of dye.